Picasso-Kent PJ new design by Hagen

hagent · Post by **hagent** » Sun Jan 21, 2007 2:11 am

Hello everyone.

I'm almost done welding up my latest PJ. The idea came about looking at Mikes Mini Kent PJ. I of course have a twisted imagination and therefore came up with this design.

It has 5 intakes. 4 smaller in length and one concentric intake that is aproximately twice as long plus %30 percent. The 30% extra was my attempt at guessing the concentric intake air/fuel temperature and compensating for the faster wave travel.

So the 4 intakes should opperate at twice the frequency of the concentric intake. Fuel will be injected at three locations around the concentric intake about 1/4" from the slight flare. I'm hoping that this will entrain air and pre-mix the fuel and raise the fuel/air temp before a final mixing in the CC.

I gass welded (acetylene/Oxygen) all parts. The CC is 304 stainless the concentric intake is 304 and the small intakes are mild steel and the exuast is mild steel.

Here are a couple of concept renderings of my new engine. I used 1.5" OD car exhaust tubing for the tail pipe.

I hope to finish welding tomorrow and maybe I'll get a chance to start it up!

Cheers!

Zippiot · Post by **Zippiot** » Sun Jan 21, 2007 2:22 am

I wanna make one that looks like a squid, then I could call it squiddy!!!

Does the red pipe extend inside the cc or does it connect with the purple pipe (think I got the colors correct cant see the pic while writing this)?

Zippiot · Post by **Zippiot** » Sun Jan 21, 2007 2:22 am

green pipe! not red

hagent · Post by **hagent** » Sun Jan 21, 2007 2:42 am

Zippiot wrote:I wanna make one that looks like a squid, then I could call it squiddy!!!

Does the red pipe extend inside the cc or does it connect with the purple pipe (think I got the colors correct cant see the pic while writing this)?

The green and purple pipes are even and do not extend into the CC.

hagent · Post by **hagent** » Sun Jan 21, 2007 2:47 am

Here is a picture of the Intake plate and CC before welding.

hagent · Post by **hagent** » Sun Jan 21, 2007 5:01 am

Some more construction photos.

hagent · Post by **hagent** » Sun Jan 21, 2007 5:59 am

More photos.

Spark plug from Eric's house of Pulse Jets. Or was that Eric's space heaters for the deaf? I can't remember.

I'm sure you have all noticed how black the areas around the welds are. That's because of the flux and the carborizing flame necessary to gas weld stainless steel. I hope it all burns off on the first run:)

Eric · Post by **Eric** » Sun Jan 21, 2007 4:44 pm

Very neat! If you have a brass bristle brush, you can get them in harbor freight, just give it a good brushing before the weld has cooled below 200-150 degrees.

If you do it then its fairly easy to brush off, but if you wait until its totally cool it can become damn near impossible to brush off by hand. The brush is soft enough not to scratch the hell out of the stainless and will do a nice job when its still warm.

Either way the engine will get pretty hot and all turn black after a while anyway :)

Eric

hagent · Post by **hagent** » Tue Jan 23, 2007 7:11 am

All my time got sucked up on Sunday shoping for windows at home depot.

So tonight I was able to weld the mild steel exhaust to the stainless steel intake by using 308 welding rod as anchors. It was a pain to get it to weld to the exhaust so I hope it will last for awhile.

The picts don't look too pretty. Not like yours Larry.

I'm hoping on going to the Camerillo airfield in Ventura county CA this Saturday with some people from work to run all my PJs.

Cheers,

hagent · Post by **hagent** » Wed Jan 24, 2007 7:00 am

Almost done!

The wify let me play with my torch in the garage tonight. I only need to make the intake extensions with flare, they will alow me to adjust the intake length.

I had real fun making the 3 tube fuel lines. I ended up brazing them onto the end of an air hose connector. It's amazing how easy the brass just disentigrated. I had to redo it once.

Here are some pictures.

Can't wait to try it out!

Cheers.

larry cottrill · Post by **larry cottrill** » Wed Jan 24, 2007 1:16 pm

hagent wrote:Almost done!

The wify let me play with my torch in the garage tonight. I only need to make the intake extensions with flare, they will alow me to adjust the intake length.

Beautiful, Hagen! I hope this works well for you.

I had real fun making the 3 tube fuel lines. I ended up brazing them onto the end of an air hose connector. It's amazing how easy the brass just disentigrated. I had to redo it once.

If you're going to braze, get copper tubing - it should stay solid even as the brazing rod melts onto it. I'm no expert on brazing, but my dad used to do a lot of it, and really preferred it to welding for a lot of things.

L Cottrill

hagent · Post by **hagent** » Wed Jan 24, 2007 9:09 pm

Great idea larry.

I think i might just have some around.....

Right now the connector appears to be air tight. I won't know till I hook it up to propane under some serious presure.

I guess I should hook it up to my air hose and see if I blow the seal...

Thanks!

Irvine.J · Post by **Irvine.J** » Thu Jan 25, 2007 12:05 am

G'day Hagent. I silver braze all my fuel lines. If you have a burnzomatic torch and a bunch of air hose connectiongs the whole process is really simple. Simply some silver solder sticks (Which can be very cheap or very expensive.) I use the cheap stuff and it still rocks! I actually put my copper line into the 1/4 inch air hose fittings, that would normally click into an air hose changing thing. The threads screw easily into any primus gas line.

The only thing you should remember is to use your flux, and make sure its sealed tightly because it dries very quickly. Flux will help it bond to other metals like I bonded my copper lines to the steel poles on my test stands. Its very easy to use.

Another thing to remember when brazing, is to try your best to keep the fitting your brazing away from a big heat sink like a vice. Clamp it in the vice so that 90% of the airhose fitting and 100% of the copper pipe is freely in the air, on a slight angle so the melting silver will flow into the gap. (Only needs a tiny angle). Heat up the fitting with the copper tube in place and you'll notice the flux bubbles, but also gets very sticky to help hold the tube in place. Take your silver stick, after about 10 seconds of gently waving the flame on the fitting and tube. (Wave it slowly till the whole area your going to put flux on is RED HOT) Then gently dab the end of the silver solder on. If it doesn't melt straight away, keep heating and gently dabing (you can heat the silver stick up a bit whilst holding it on the fitting and it might just start flowing. All of a sudden it will flow like syrip and completely fill the cavity, gently move the stick around, and whallah. VERY strong seal, I've never had any leakage even in extremely high pressure lines. Its actually MUCH harder to drill then the copper itself.

Its really very easy, and if you practice it once or twice, you'll nail it every time. Just remember to not to entirely clamp it in the vice or it simply will not get hot enough as all the heat goes into the vice and the attachment wont get red hot at all.

hagent · Post by **hagent** » Thu Jan 25, 2007 12:29 am

Thanks Irvine for the info.

In the pictue above I used my acyetelen / oxy gas welder setup. I had to be real careful not to melt the brass fitting. I was holding the flame like 12" away form the part.

I used silver brazing solder the not so cheap one from home depot. It has the blue flux around the stick. I might just have to go back to the welding supply store and get me some wipe on flux and cheap silver brazing rod. The other stuff was like 6 bucks for about two 18" sticks.

Thanks again.

hagent · Post by **hagent** » Fri Jan 26, 2007 5:56 am

Well it's DONE!

haven't tryed it yet. May have to wait till Saturday. I really have a burning desire to put some ethanol in the CC and see what happens.

Here are some more pictures.

One is with the extensions. They are a little large on the diameter, but the closest I could find to fit.

The other pictures are of a new injector that I thought of today. It's plain old copper tubing that has been pinched at one end (hammered) and then with a dremel cutting wheel I cut into the metal until a small opening emerged. I did this on both sides of the pinch. I then did another pinch about 1/2 an inch away at 90 degrees to the first, but did not pinch it all the way. I was hoping for a bulge that would allow me to cut away enough material to get an angle of around 45 degrees to the intake flow. It came out quite nice and I will try it on Saturday with Bills PJ design. I wonder if I will get better results than my concentric fuel feed. I also have to make Bills injector per spec and try that too.

Well I can't wait for Saturday!

Cheers.